<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Validate
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Abstract.php 18951 2009-11-12 16:26:19Z alexander $
 */

/**
 * @see Zend_Validate_Abstract
 */
require_once 'Zend/Validate/Abstract.php';

/**
 * Class for Database record validation
 *
 * @category   Zend
 * @package    Zend_Validate
 * @uses       Zend_Validate_Abstract
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Validate_Db_Abstract extends Zend_Validate_Abstract
{
	/**
	 * Error constants
	 */
	const ERROR_NO_RECORD_FOUND = 'noRecordFound';
	const ERROR_RECORD_FOUND    = 'recordFound';

	/**
	 * @var array Message templates
	 */
	protected $_messageTemplates = array(self::ERROR_NO_RECORD_FOUND => 'No record matching %value% was found',
	self::ERROR_RECORD_FOUND    => 'A record matching %value% was found');

	/**
	 * @var string
	 */
	protected $_schema = null;

	/**
	 * @var string
	 */
	protected $_table = '';

	/**
	 * @var string
	 */
	protected $_field = '';

	/**
	 * @var mixed
	 */
	protected $_exclude = null;

	/**
	 * Database adapter to use. If null isValid() will use Zend_Db::getInstance instead
	 *
	 * @var unknown_type
	 */
	protected $_adapter = null;

	/**
	 * Provides basic configuration for use with Zend_Validate_Db Validators
	 * Setting $exclude allows a single record to be excluded from matching.
	 * Exclude can either be a String containing a where clause, or an array with `field` and `value` keys
	 * to define the where clause added to the sql.
	 * A database adapter may optionally be supplied to avoid using the registered default adapter.
	 *
	 * @param string||array $table The database table to validate against, or array with table and schema keys
	 * @param string $field The field to check for a match
	 * @param string||array $exclude An optional where clause or field/value pair to exclude from the query
	 * @param Zend_Db_Adapter_Abstract $adapter An optional database adapter to use.
	 */
	public function __construct($table, $field, $exclude = null, Zend_Db_Adapter_Abstract $adapter = null)
	{
		if ($adapter !== null) {
			$this->_adapter = $adapter;
		}
		$this->_exclude = $exclude;
		$this->_field   = (string) $field;

		if (is_array($table)) {
			$this->_table  = (isset($table['table'])) ? $table['table'] : '';
			$this->_schema = (isset($table['schema'])) ? $table['schema'] : null;
		} else {
			$this->_table = (string) $table;
		}

	}

	/**
	 * Run query and returns matches, or null if no matches are found.
	 *
	 * @param  String $value
	 * @return Array when matches are found.
	 */
	protected function _query($value)
	{
		/**
		 * Check for an adapter being defined. if not, fetch the default adapter.
		 */
		if ($this->_adapter === null) {
			$this->_adapter = Zend_Db_Table_Abstract::getDefaultAdapter();
			if (null === $this->_adapter) {
				require_once 'Zend/Validate/Exception.php';
				throw new Zend_Validate_Exception('No database adapter present');
			}
		}

		/**
		 * Build select object
		 */
		$select = new Zend_Db_Select($this->_adapter);
		$select->from($this->_table, array($this->_field), $this->_schema)
		->where($this->_adapter->quoteIdentifier($this->_field).' = ?', $value);
		if ($this->_exclude !== null) {
			if (is_array($this->_exclude)) {
				$select->where($this->_adapter->quoteIdentifier($this->_exclude['field']).' != ?', $this->_exclude['value']);
			} else {
				$select->where($this->_exclude);
			}
		}
		$select->limit(1);

		/**
		 * Run query
		 */
		$result = $this->_adapter->fetchRow($select, array(), Zend_Db::FETCH_ASSOC);

		return $result;
	}
}
